Bio Lecture Exam #2 Flashcards
(120 cards)
1
Q
What is energy?
A
Energy is the capacity to do work or produce change, existing in various forms that can be converted but not created or destroyed.
2
Q
What are the main forms?
A
1: Kinetic
2: Potential
3: Chemical
4: Radiant/Solar
3
Q
What is kinetic energy?
A
The energy of motion
4
Q
What is potential energy?
A
Stored or chemical energy
5
Q
What is chemical energy?
A
Chemical energy is the energy stored in the bonds of chemical compounds, such as molecules and atoms, which can be released or absorbed during a chemical reaction
6
Q
What is an endergonic reaction?
A
An endergonic reaction is a chemical reaction that needs energy to happen, leading to products that have more energy than what you started with.
7
Q
What is an exergonic reaction?
A
An exergonic reaction is a chemical reaction that releases energy, resulting in products that have less energy than the reactants.
8
Q
What is an anabolic reaction?
A
An anabolic reaction is a chemical process that builds larger, more complex molecules from smaller ones, requiring energy input, such as forming proteins from amino acids.
9
Q
What is a catabolic reaction?
A
A catabolic reaction is a chemical process that breaks down larger, complex molecules into smaller ones, releasing energy in the process, such as breaking down glucose during digestion.
10
Q
What is the ADP-ATP cycle?
A
The ADP-ATP cycle is a process where adenosine triphosphate (ATP) releases energy by breaking down into adenosine diphosphate (ADP) and a phosphate group. This released energy powers cellular activities. When energy is available, ADP can be recharged back into ATP through processes like cellular respiration, storing energy for future use.
11
Q
What is cellular respiration?
A
Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.
12
Q
What is the equation for cellular respiration?
A
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
(Glucose + Oxygen yields Carbon Dioxide + Water + ATP or Energy)
13
Q
What is cellular respiration for?
A
Cellular respiration converts the energy in glucose into ATP, providing the energy necessary for cells to perform essential functions.
14
Q
Breakdown of Glycolysis
A
1st step of cellular respiration
Where It Happens: Cytoplasm of the cell
What Goes In: 1 glucose molecule (C₆H₁₂O₆)
What Comes Out: 2 pyruvate molecules, 2 ATP, and 2 NADH
What Is Made: Energy (ATP) and electron carriers (NADH)
15
Q
What is pyruvate?
A
Pyruvate is a 3-carbon molecule that is produced from the breakdown of glucose during glycolysis.
16
Q
What is NADH and NADH+?
A
NADH and NADH+ are molecules that carry electrons. NADH carries electrons, while NADH+ does not. These molecules are important for transferring energy from glucose to ATP in cellular respiration.
17
Q
What is the Citric Acid (Krebs) Cycle?
A
The citric acid cycle is a series of chemical reactions that occurs in mitochondria. It breaks down acetyl-CoA into carbon dioxide, releasing energy used to produce ATP. This cycle is essential for cellular respiration.
18
Q
Breakdown of Citric Acid Cycle
A
Happens in: Mitochondrial matrix
What Goes In: 2 pyruvate molecules (from glycolysis) converted to acetyl-CoA
What Comes Out: 6 CO₂, 2 ATP, 6 NADH, and 2 FADH₂
What Is Made: Energy (ATP) and electron carriers (NADH and FADH₂)
19
Q
What is FADH and FADH2?
A
FAD and FADH2 are molecules that carry electrons. FAD does not carry electrons, while FADH2 does. These molecules are important for the Krebs cycle and contribute to ATP production.
20
Q
What is the Electron Transport Chain (ETC)?
A
The electron transport chain is a series of protein complexes in mitochondria. Electrons are passed through these complexes, releasing energy used to pump protons. This proton gradient drives ATP synthesis
21
Q
Breakdown of Electron Transport Chain
A
Happens in: Inner mitochondrial membrane
What Goes In: NADH and FADH₂ (from glycolysis and Krebs cycle), and oxygen (O₂)
What Comes Out: 32-34 ATP and water (H₂O)
What Is Made: Large amounts of energy (ATP) and water
22
Q
What is the role of oxygen?
A
Oxygen plays a crucial role in cellular respiration as the final electron acceptor in the electron transport chain (ETC). It helps produce ATP by combining with electrons and protons to form water, allowing the entire process to continue and efficiently generate energy for the cell.
23
Q
What is Photosynthesis?
A
Photosynthesis is the process by which plants convert sunlight into energy, using carbon dioxide and water to produce glucose and oxygen.
24
Q
What is the equation for photosynthesis?
A
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
25
What is made in the photosynthesis equation?
6 carbon dioxide molecules and 6 water molecules, using sunlight as energy, produce 1 glucose molecule and 6 oxygen molecules.
26
Where is it made?
Photosynthesis takes place in the chloroplasts of plant cells. These organelles contain chlorophyll, a pigment that absorbs sunlight and uses its energy to drive the chemical reactions involved in photosynthesis.
27
What is Light Reaction?
The light reaction in photosynthesis is the first stage that occurs in the thylakoid membranes of chloroplasts, where sunlight is captured and used to split water molecules, releasing oxygen, and producing energy-rich compounds like ATP and NADPH.
28
What is the Calvin Cycle?
The Calvin cycle is the second stage of photosynthesis, occurring in the stroma of chloroplasts, where carbon dioxide is converted into glucose using the energy from ATP and NADPH produced in the light reactions.
29
Where does each happen?
The light reaction occurs in the thylakoid membranes of chloroplasts, while the Calvin cycle takes place in the stroma of chloroplasts.
30
What happens in Light Reaction?
In the light reaction, sunlight is captured to split water molecules, releasing oxygen and generating energy-rich ATP and NADPH.
31
What happens in Calvin Cycle?
In the Calvin cycle, carbon dioxide is transformed into glucose using the ATP and NADPH produced during the light reactions.
32
What are the inputs and outputs of both?
Light Reaction
- Inputs: Water (H₂O) and sunlight
- Outputs: Oxygen (O₂), ATP, and NADPH
Calvin Cycle
- Inputs: Carbon dioxide (CO₂), ATP, and NADPH
- Outputs: Glucose (C₆H₁₂O₆), ADP, and NADP⁺
33
What is the cell cycle?
The cell cycle is the series of stages that a cell goes through to grow, replicate its DNA, and divide into new cells. It includes interphase for growth and preparation, followed by the division phases that result in cell division.
34
What is Interphase?
Interphase: The phase before mitosis, where the cell prepares for division. It includes:
-G1 (gap 1): Cell growth, protein synthesis, and organelle production.
- S (synthesis): DNA replication.
- G2 (gap 2): Further growth, protein production, and preparation for mitosis.
35
What is Prophase?
The first step of mitosis is prophase, where the chromatin condenses into visible chromosomes, the nuclear envelope begins to break down, and the spindle fibers start to form and attach to the chromosomes.
36
What is Metaphase?
Step 2 of mitosis is metaphase. During metaphase, the chromosomes align along the cell's equatorial plane, known as the metaphase plate, and the spindle fibers attach to the centromeres of the chromosomes, preparing them for separation.
37
What is Anaphase?
Step 3 of mitosis is anaphase. During anaphase, the spindle fibers pull the sister chromatids apart at the centromeres, separating them and moving them toward opposite poles of the cell.
38
What is Telophase?
Step 4 of mitosis is telophase. During telophase, the separated chromatids reach the opposite poles of the cell, the nuclear envelope reforms around each set of chromosomes, and the chromosomes begin to de-condense back into chromatin, marking the near end of mitosis.
39
What is Cytokinesis?
After telophase, cytokinesis occurs, which is the process where the cytoplasm divides, resulting in two separate daughter cells. In animal cells, this is achieved through the formation of a cleavage furrow, while in plant cells, a cell plate forms to separate the two new cells.
40
What is M phase?
M phase, or mitotic phase, refers to the stage of the cell cycle where mitosis and cytokinesis occur, leading to cell division. It encompasses the processes of prophase, metaphase, anaphase, telophase, and concludes with cytokinesis, resulting in two genetically identical daughter cells.
41
Where Mitosis happens:
1. Prophase: (Nucleus/Cytoplasm) Chromatin condenses, nuclear envelope breaks down, spindle fibers form.
2. Metaphase: (Equatorial plane) Chromosomes align at the metaphase plate; spindle fibers attach to centromeres.
3. Anaphase: (Cytoplasm) Sister chromatids are pulled apart to opposite poles.
4. Telophase: (Near poles) Nuclear envelope reforms; chromosomes de-condense.
5. Cytokinesis: (Cytoplasm) Cytoplasm divides, forming two daughter cells (cleavage furrow in animals, cell plate in plants).
42
What is Mitosis for?
Mitosis is the process by which a cell divides its nucleus and genetic material to produce two genetically identical daughter cells, essential for growth, tissue repair, and asexual reproduction.
43
How many cells (called what) are produced at the end?
At the end of mitosis, two genetically identical diploid daughter cells are produced.
44
Plant vs Animal Cytokinesis
Animal Cells: Cytokinesis occurs through the formation of a cleavage furrow that pinches the cell membrane inward, separating the two daughter cells.
Plant Cells: Cytokinesis involves the formation of a cell plate that develops in the center of the cell, eventually becoming the new cell wall, separating the daughter cells.
45
What is Meiosis?
Meiosis is a specialized type of cell division that reduces the chromosome number by half.
- Purpose: Produces four genetically diverse haploid gametes (sperm or eggs).
- Phases: Consists of two rounds of division: meiosis I and meiosis II.
- Genetic Variation: Involves crossing over and independent assortment, increasing genetic diversity.
- Location: Occurs in germ cells in the ovaries and testes.
46
What is Meiosis for?
- Purpose: Produces gametes (sperm and eggs) with half the chromosome number.
- Importance: Ensures correct chromosome number at fertilization and promotes genetic diversity through crossing over and independent assortment.
47
What is the 1st stage of Meiosis?
The first stage of meiosis is prophase I. During this stage, homologous chromosomes pair up and undergo crossing over, exchanging genetic material, while the nuclear envelope begins to break down and spindle fibers form.
48
What is the 2nd stage of Meiosis?
The second stage of meiosis is metaphase I. During this stage, homologous chromosome pairs align along the metaphase plate, and spindle fibers attach to the centromeres of each chromosome.
49
What is the 3rd stage of Meiosis?
The third stage of meiosis is anaphase I. During this stage, the homologous chromosomes are pulled apart by spindle fibers and moved toward opposite poles of the cell, while sister chromatids remain attached at their centromeres.
50
What is the 4th stage of Meiosis?
The fourth stage of meiosis is telophase I. During this stage, the separated homologous chromosomes reach the opposite poles, the nuclear envelope may reform around each set of chromosomes, and the cell prepares to divide, leading to cytokinesis.
51
Cytokinesis I in Meiosis
Cytokinesis I in meiosis occurs after telophase I, dividing the cytoplasm of two daughter cells. In animal cells, a cleavage furrow forms, while in plant cells, a cell plate develops, resulting in two haploid cells, each with chromosomes still consisting of sister chromatids.
52
What is Meiosis II?
Meiosis II is the second round of division that separates sister chromatids in the two haploid cells produced from meiosis I, resulting in four genetically diverse haploid gametes.
53
Stages of Meiosis II:
1. Prophase II: Chromosomes condense, and the nuclear envelope breaks down if it reformed; spindle fibers form.
2. Metaphase II: Chromosomes align along the metaphase plate; spindle fibers attach to centromeres.
3. Anaphase II: Sister chromatids are pulled apart to opposite poles of the cell.
4. Telophase II: Nuclear envelopes reform around each set of chromosomes; chromosomes begin to de-condense.
5. Cytokinesis II: Cytoplasm divides, resulting in four genetically diverse haploid cells.
54
How many cells (called what) are produced at the end of Meiosis?
At the end of meiosis II, a total of four genetically diverse haploid cells (gametes) are produced from the two haploid cells formed in meiosis I.
55
Meiosis & Mitosis Similarities
- Both are processes of cell division.
- Both involve the stages of prophase, metaphase, anaphase, and telophase.
- Both start after DNA replication during interphase.
- Both result in the separation of genetic material to form new cells.
- Both involve the formation of spindle fibers that assist in chromosome movement.
56
Meiosis & Mitosis Differences
- Number of Divisions: Mitosis involves one division; meiosis involves two divisions (meiosis I and II).
- Number of Cells Produced: Mitosis produces two genetically identical diploid cells; meiosis produces four genetically diverse haploid cells.
- Genetic Variation: Mitosis results in identical daughter cells; meiosis promotes genetic diversity through crossing over and independent assortment.
- Purpose: Mitosis is for growth and tissue repair; meiosis is for producing gametes for sexual reproduction.
- Chromosome Number: Mitosis maintains the same chromosome number; meiosis reduces the chromosome number by half.
57
Who was Gregor Mendel and what was he famous for?
Gregor Mendel was a 19th-century Austrian monk and scientist known as the father of modern genetics. He is famous for his pioneering experiments with pea plants, which established the basic laws of inheritance, including the concepts of dominant and recessive traits.
58
What is a trait?
A trait in genetics is a specific characteristic or feature of an organism, such as eye color or height, that is influenced by its genetic makeup. Traits can be inherited from parents and can be affected by environmental factors.
59
What is a gene?
A gene is a segment of DNA that codes for a specific protein or RNA molecule. It is the fundamental unit of heredity and carries the instructions for building and maintaining an organism.
60
What is an allele?
An allele is a variant form of a gene that can produce different traits in an organism. Each individual typically inherits two alleles for each gene, one from each parent, which can be either identical or different.
61
What is a dominant?
Dominant refers to an allele that expresses its trait even when only one copy is present, overshadowing the effect of a recessive allele.
62
What is recessive?
Recessive is an allele that shows its trait only when two copies are present, meaning it is hidden by a dominant allele when they are together (heterozygous)
63
What does Heterozygous mean?
Heterozygous means having two different alleles for a particular gene, one inherited from each parent.
64
What does Homozygous mean?
Homozygous means having two identical alleles for a particular gene, either both dominant or both recessive.
65
What is a genotype?
A genotype is the genetic makeup of an individual, specifically the combination of alleles that an individual inherits for a particular trait. It is the underlying genetic code that determines the individual's characteristics.
66
What is a phenotype?
A phenotype is the visible traits or characteristics of an organism, like its color, size, or shape. These traits come from the organism's genes and how they interact with the environment.
67
What is the Law of Segregation?
The Law of Segregation is one of Mendel's laws of inheritance, stating that during gamete formation, each allele of a pair separates from the other, so that each gamete receives only one allele.
68
What is Incomplete Dominance?
Incomplete dominance is a genetic situation where neither allele is completely dominant over the other, resulting in a blend of traits in the offspring. For example, if a red flower (RR) is crossed with a white flower (WW), the offspring might be pink (RW), showing a mix of both parental traits.
69
What is Co-Dominance?
Co-dominance is a genetic situation where both alleles in a gene pair are fully expressed in the offspring, resulting in a phenotype that shows both traits distinctly. For example, in a flower with one red allele (R) and one white allele (W), the offspring might have petals that are both red and white, rather than blending into a new color like in incomplete dominance.
70
Mendelian Vs Polygenic Inheritance
Mendelian Inheritance
- Involves single genes with dominant and recessive alleles.
- Clear phenotype categories (e.g., tall vs. short).
- Examples: flower color in peas, pea shape.
Polygenic Inheritance
- Involves multiple genes influencing a single trait.
- Results in a continuous range of phenotypes.
- Examples: skin color, height, and eye color.
71
Relationship between Genes & Environment
Genes provide the biological framework for an organism's traits, while environmental factors influence how these genes are expressed. This interplay shapes development, behavior, and overall health, highlighting the significance of both nature and nurture.
72
Developmental Plasticity
Developmental plasticity is the capacity of an organism to adapt its growth and development in response to environmental changes.
73
What is Acclimation?
Acclimation is the process by which an organism gradually adjusts to changes in its environment, allowing it to maintain performance and function despite those changes, typically occurring over a short time frame. It is not heritable, but it is reversible
74
What are Autosomal Genetic Disorders?
Autosomal genetic disorders are caused by mutations in genes on the non-sex chromosomes and can be inherited in dominant or recessive patterns. Examples include cystic fibrosis (recessive), Huntington's disease (dominant), sickle cell disease (recessive)
75
Autosomal Disorders: Dominant
Dominant: A disorder is considered dominant if only one copy of the mutated gene (from either parent) is needed for the disorder to appear. This means that if one parent has the dominant gene for the disorder, there is a 50% chance their child will inherit it.
76
Autosomal Disorders: Recessive
A disorder is recessive if two copies of the mutated gene (one from each parent) are needed for the disorder to manifest. If a child inherits only one recessive gene and one normal gene, they won't have the disorder but can be a carrier, potentially passing the recessive gene to their children.
77
What is X-Linked Inheritance?
X-linked inheritance refers to the pattern of inheritance for genes located on the X chromosome, one of the two sex chromosomes
78
X-Linked: Males
Males (XY): Males have one X and one Y chromosome. If they inherit an X-linked recessive gene, they will express the trait or disorder because they don't have a second X chromosome to mask it. This means conditions like hemophilia and color blindness are more common in males.
79
X-Linked: Females
Females (XX): Females have two X chromosomes. To express an X-linked recessive trait, they need two copies of the mutated gene (one from each parent). If they have just one mutated gene, they can be carriers but usually do not show symptoms.
80
Examples of X-Linked Disorders:
Hemophilia: A bleeding disorder that affects blood clotting, more common in males.
Color Blindness: Difficulty distinguishing certain colors, primarily affects males.
Duchenne Muscular Dystrophy (DMD): A severe muscle weakness disorder that mainly affects boys.
81
Who discovered the structure of DNA?
James Watson and Francis Crick
82
Whose x-ray image helped them?
Rosalind Franklin's
83
What is the structure of DNA?
Double helix
1. Two Strands: DNA consists of two long strands of nucleotides that run in opposite directions (antiparallel).
2. Nucleotides: Each nucleotide is made up of a sugar (deoxyribose), a phosphate group, and a nitrogenous base.
3. Base Pairing: The rungs of the ladder are formed by pairs of nitrogenous bases: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
4. Backbone: The sides of the ladder are made of alternating sugar and phosphate groups.
This structure allows DNA to store genetic information and replicate accurately during cell division.
84
What are the monomers of DNA?
The monomers of DNA are nucleotides
85
What is each DNA monomer made of?
Sugar molecule: This is a deoxyribose sugar, a five-carbon sugar.
Phosphate group: This is a negatively charged group containing phosphorus.
Nitrogenous base: There are four types: adenine (A), guanine (G), cytosine (C), and thymine (T).
86
How does DNA replicate?
DNA replicates by unwinding its double helix structure, where each strand serves as a template for creating a new complementary strand. Enzymes help match the correct building blocks to each template, resulting in two identical DNA molecules.
87
Why is DNA replication semi-conservative?
DNA replication is called semi-conservative because each new DNA molecule consists of one original strand and one newly synthesized strand. This method helps preserve the genetic information while also allowing for accurate copying during cell division.
88
Why is DNA read from 3-5, but built from 5-3?
DNA is read from 3' to 5' to allow the enzyme to access the template strand correctly, while it is built from 5' to 3' because of the way DNA polymerase functions. This anti-parallel nature of DNA strands is essential for accurate replication and transcription.
89
What is helicase?
Helicase is an enzyme that unwinds the double-stranded DNA helix during replication. It separates the two strands of DNA, allowing other enzymes, like DNA polymerase, to access the individual strands and copy them.
90
What is DNA Polymerase?
DNA polymerase is an enzyme that synthesizes new DNA strands during replication. It adds nucleotides to a growing DNA strand based on the sequence of the template strand, ensuring accurate copying of genetic information. Additionally, some types of DNA polymerase also have proofreading abilities to correct any errors.
91
What is Topoisomerase?
Topoisomerase is an enzyme that helps relieve the tension and twisting that occurs in DNA when it is unwound during replication. It cuts the DNA strands to temporarily relax the supercoiling, then re-joins them, ensuring the DNA can be properly replicated without getting tangled.
92
What is Primase?
Primase is an enzyme that synthesizes short RNA primers during DNA replication. These primers provide a starting point for DNA polymerase to begin adding DNA nucleotides, as DNA polymerase cannot start a new strand on its own.
93
What is DNA Ligase?
DNA ligase is an enzyme that joins together DNA fragments during replication. It connects the gaps between Okazaki fragments on the lagging strand, sealing the sugar-phosphate backbone to create a continuous DNA strand.
94
What is the Leading Strand?
The leading strand is the DNA strand that is synthesized continuously during DNA replication. It is built in the same direction as the replication fork is opening, allowing DNA polymerase to add nucleotides smoothly as the DNA unwinds.
95
What is the Lagging Strand?
The lagging strand is the DNA strand that is synthesized in short, discontinuous segments during DNA replication. It is built in the opposite direction of the replication fork, which means it requires multiple RNA primers and the formation of Okazaki fragments that are later joined together by DNA ligase.
96
What is a mutation?
A mutation is a change in the DNA sequence of an organism. These changes can occur naturally or due to environmental factors and can affect how genes function, potentially leading to variations in traits, diseases, or even evolutionary changes.
97
What is a point mutation?
A point mutation is a change in just one building block of DNA. This can mean swapping one base for another, which might change a protein or have no effect at all.
98
What is a silent mutation?
A silent mutation is a change in the DNA that doesn't affect the protein made by that gene. Even though one building block of DNA is changed, it still codes for the same amino acid, so the protein remains the same.
99
What is a missense mutation?
A missense mutation is a change in the DNA that results in the substitution of one amino acid for another in a protein. This can alter the protein's function, potentially leading to changes in traits or health.
100
What is a nonsense mutation?
A nonsense mutation is a change in the DNA that creates a premature stop signal in the protein sequence. This leads to a shorter, incomplete protein, which can affect its function and may cause health problems.
101
What is an Insertion Frameshift?
An insertion frameshift is a mutation where extra nucleotides are added to the DNA sequence. This shifts the reading frame of the genetic code, changing how the sequence is read and potentially altering all the amino acids that follow, which can significantly affect the resulting protein.
102
What is a Deletion Frameshift?
A deletion frameshift is a mutation where one or more nucleotides are removed from the DNA sequence. This shifts the reading frame of the genetic code, altering how the sequence is read and potentially changing all the amino acids that follow, which can drastically affect the resulting protein's function.
103
Which kinds of mutations are heritable?
Heritable mutations are those that occur in the DNA of germ cells (sperm and egg). This includes:
1. Point mutations (silent, missense, and nonsense mutations)
2. Insertions
3. Deletions
4. Frameshift mutations
If these mutations are present in germ cells, they can be passed on to offspring, potentially affecting their traits or health.
104
Which kinds of mutations aren't heritable?
Mutations that are not heritable typically occur in somatic cells, meaning they happen in non-reproductive cells and cannot be passed to offspring. These include:
1. Somatic point mutations
2. Insertions and deletions in somatic cells
3. Frameshift mutations in somatic cells
These mutations can affect the individual organism, such as leading to cancer, but they won't be passed on to the next generation.
105
What are mutagens?
Mutagens are substances or factors that can cause changes (mutations) in the DNA sequence. They can be physical agents, like radiation (e.g., UV light, X-rays), or chemical agents, such as certain chemicals in tobacco smoke or industrial pollutants. Mutagens increase the likelihood of mutations occurring, which can lead to various health issues, including cancer.
106
Mutations and Evolution
Mutations introduce genetic variation, which is essential for evolution. Beneficial mutations can enhance an organism's survival and reproduction, leading to the adaptation of species over time.
107
What is Protein Synthesis?
Protein synthesis is the process by which cells create proteins based on the information encoded in DNA. It involves two main steps: transcription, where DNA is converted into messenger RNA (mRNA), and translation, where the mRNA is used to assemble amino acids into a protein.
108
What is the Central Dogma?
The central dogma of molecular biology describes the flow of genetic information in cells: it states that DNA is transcribed into RNA, which is then translated into proteins. This process explains how the information in genes leads to the production of proteins that carry out various functions in the organism.
109
What is Transcription?
Transcription is the process by which the information in a DNA sequence is copied into a messenger RNA (mRNA) molecule. During transcription, an enzyme called RNA polymerase reads the DNA strand and synthesizes the mRNA, which then carries the genetic information from the nucleus to the ribosomes for protein synthesis.
110
What is a codon?
A codon is a sequence of three nucleotides in messenger RNA (mRNA) that corresponds to a specific amino acid or a stop signal during protein synthesis. Each codon determines which amino acid will be added next in the growing protein chain.
111
What is Translation?
qasdadr5sdx
112
What are the 3 binding sites in a ribosome?
1. A site (Aminoacyl site): The entry point for new tRNA molecules carrying amino acids.
2. P site (Peptidyl site): The location where the growing polypeptide chain is held, and where tRNA carries the amino acid that is being added to the chain.
3. E site (Exit site): The site where tRNA, after donating its amino acid, exits the ribosome.
113
How are genes regulated?
Gene regulation controls which genes are turned on or off in a cell. This is influenced by factors like promoters, enhancers, repressors, and epigenetics. The regulation process involves steps like transcription, translation, and post-translational modifications, ensuring precise gene expression.
114
How much human DNA codes for proteins?
About 1-2% of human DNA codes for proteins. This protein-coding DNA consists of genes, while the majority of the genome includes non-coding regions that have other regulatory and structural roles.
115
What does the rest of human DNA do?
- Most non-coding human DNA regulates gene expression and produces non-coding RNAs, like rRNA and tRNA.
- It includes introns, which are removed during RNA processing, and repetitive sequences that support chromosome structure and stability.
- These non-coding regions are vital for gene regulation and overall cellular function.
116
What is Alternative Splicing?
Alternative splicing is a process that allows a single gene to produce multiple proteins. Different sections of an RNA transcript can be removed or retained, resulting in different mRNA molecules and proteins.
117
What are introns?
Introns are non-coding sequences of DNA that are transcribed into RNA but are then removed before the RNA is translated into protein. They are found between the coding regions of genes, called exons. The removal of introns from RNA is a process called splicing, which is essential for producing functional proteins.
118
What are Exons?
Exons are the coding regions of a gene that contain the information needed to produce a protein. During RNA processing, exons are spliced together to form the final messenger RNA (mRNA) molecule, which is then translated into a protein.
119
Why are humans more complex than organisms with the same number of genes?
Alternative splicing enables a single gene to produce multiple protein variants, increasing the functional diversity of proteins. This allows humans to have greater complexity in biological functions and adaptations compared to organisms with the same number of genes.
120
What is Glycolysis?
Glycolysis is a process that breaks down glucose into pyruvate to produce energy. It occurs in the cytoplasm of cells and doesn’t require oxygen. This process generates a small amount of energy and is the first step in converting food into usable energy.
